The present invention relates to a system for fastening interchangeable advertisements to a supporting strip wound and unwound between at least two parallel rollers.
Various types of devices are known for displaying a series of advertisements in a display window, e.g. a transparent window with back lighting. On one known device, the advertisements are joined into a strip which is fed back and forth on rollers for selecting and displaying a given advertisement.
A major drawback of this type of device is that, to change one or more of the advertisements, the entire strip must be dismantled and the advertisements formed into a new strip, which operation involves considerable downtime during which the device, if used commercially for several advertisers with different display schedules, is substantially unusable.
On another known device, the strip is fed along an endless path defined by a series of parallel guide rollers about which the strip is wound and fed in one direction only, and a removable fastening system is provided for fastening the advertisements in interchangeable manner to the strip.
The fastening system comprises a strip of adhesive material placed on, and perpendicular to the traveling direction of, the supporting strip at the required location of the leading edge of the advertisement. Due to the difference in the winding diameter of the advertisement and the underlying supporting strip, however, the advertisement, as it travels over the rollers, slides in relation to the supporting strip, for which reason, the trailing edge of the advertisement is left unfastened to enable it to slide freely in relation to the supporting strip.
Such a system, however, is unsuitable for display devices wherein the supporting strip is wound and unwound between two rollers rotating in both directions. In this case in fact, while moving freely in relation to the supporting strip as this travels in one direction, the free edge of the advertisement cannot be fed forward when the supporting strip is inverted, which would require feeding the free edge forward in relation to the supporting strip and inserting it inside the turn of the supporting strip on the roller.